Process of treating and manufacturing steel.



PATENTED APR. 19, 1904.

W. BURROW' PROCESS OF TREATING AND MANUFACTURING STEEL.

APPLIGATION IILED MAY 17, 1902.

N0 MODEL.

Patented April 19, 1904.

PATENT OEEIcE.

WVALTER B. BURROIV, OF NORFOLK, VIRGINIA.

PROCESS OF TREATING AND MANUFACTURING STEEL.

SPECIFICATION forming'part of Letters Patent No. 757,803, datedApril 19,1904. Application filed May 17, 1902. Serial No. 107,817. (Nospecimens.)

T0 aZZ whmn it may concern.-

Be it known that I, WALTER B. BURRow, a citizen of the United States,residing at N orfolk, in the county of Norfolk and State of Virginia,have invented a new and useful Process of Introducing Dephosphorizingand Desulfurizing Agents or Compounds into Molten Iron and Steel; and Ido declare that the following is a full, clear, and exact description ofthe same.

My invention relates to the method of treatment and the manufacture ofsteel and similar products.

The process consists of injecting into the molten iron or steelfinely-divided dephosphorizing and desulfurizing material into variousdepths or thickness of the molten metallic bath, carried in with theatmospheric air-blast at a greater or less pressure or volume.

Figure l is a sectional elevation at right angles to the axis of theconverter. Fig. 2 is a sectional elevation parallel with the axis ortrunnions. Fig. 3 is a sectional plan on the line 1 2 in Fig. l.

In the drawings, in which like letters of reference indicate similarparts in all the views, A is the converter-shell. lining. G is thebottom or main wind-box. D is the air-space or reservoir for the maintwyers or blast-orifices K.

E, E and E are thecompartments into which the auxiliary wind-box orreservoir E is divided.

E represents division-plates which separate the wind-box E into as manyparts as there are twyers in each circular row.

F represents division plates, which are placed horizontally and formcompartments in the direction-of the height of the wind-box E, as shownin Figs. 1, 2, and 3.

G is the main blast or bustle pipe surrounding the converter-body at orbelow the axis or trunnions and having one end connected to theblast-trunnion'M. I

H represents the branch pipes from the bustle-pipe G, conveying theblast to the windbox E by means of the short nipples I, Fig. 3.

J represents the side twyers, through which the pulverulent purifyingmaterial is intro- B is the refractory.

duced into the converter at different depths of the molten bath.

L is the vacuum-pipe from the interior of the converter near its outletand above the surface of the molten metal and its lower end connected tothe vacuum-trunnion M by which the products of combustion are withdrawnand a rarefied condition produced within the converter by suitablemeans.

N is a door or cover on the converter nose or outlet for closing sameand making an airtight joint.

O is a hinge for the cover N, and P is a lever or rod for operating thesame.

The air blast is used alone or mixed with variable percentages of othersuitable gases. Toward the last stage of the process a vacuum isproduced within the converter or vessel by means of an air orvacuum-pump, and the rarefied condition thus produced draws in theremainder of the purifying agents and removes the occluded gases fromthe molten metal, as will be described hereinafter. The pulverulentpurifying material is carried in with the blast and by suitableatomizers is sprayed into the iron or steel by means of rectangulartwyers or blowpipes arranged one above the other in the sides or body ofthe converting vessel and are spaced vertically downward from thetrunnion or axis to the hearth or bot tom of the converter. Eachvertical row of the side twyers is opposite another set and blow againsteach other and meeting the blast from the bottom twyers cause everyparticle of the purifying material to become intimately mixed with themolten metal. The side twyers are spaced a few inches apart from thebottom or hearth of the converter upward, so that the top ones are afraction of an inch under the level of the metal, while the lowest onesare several inches from the bottom of the converter-lining. Theconverter is provided with a jacket around its circumference,dividedinto compartmentsdownward, and each division is connected with one ormore side twyers and controlled by a valve, so that any or all of theside twyers can be cutoff and on as required. The purifying material indry powder is placed in the compartments into which the jacket isdivided and by suitable atomizers, blowpipes, and deflecting-plates isblown into the molten bath, as described. When the period of blowing isor nearly finished, the remaining charge of the purifying agents isdrawn in by closing the nose or outlet of the converter bya operation alarge quantity is drawn in by the:

vacuum and allowed to remain in for a short time, so that thematerialinjected becomes .Any occluded gases remaining in the moltensaturated with the impurities in the metal.

' bath at the conclusion or produced on the init is removed and themetal cast into suitable troduction ofithe larger amounts of thepurifying agents intojthe iron or steel are withdrawn by the vacuum-pumpand the rarefied condition kept up for several minutes according to thecondition of the metal. mulation of slag is removed from the surface ofthe metal at intervals, the slag opening or door being near the level ofthe metal.

After the process is finished and should it be necessary the metal ispoured into ladles and placed on a table and subjected to a rapid rotarymotion in order to bring all the slag to,

the surface by centrifugal force, after which molds. The pressure of theblast at the lower twyers is greater than those nearer the surface ofthe metal. The different pressures are obtained by the use ofreducing-valves supplied with the blast from a reservoir or from theaxis or trunnions of the converter, as is the usual case in the ordinarymovable or tilting converter. The air blown in by the side twyers andcarrying the finely-divided purifying material is adjusted so that theproper volume of air is injected or blown in to effect decarbonizationin conjunction with the main bottom twyers and the proper pres sure iscontrolled by valves connected to the divisions of the jacket, which isthe receptacle for the pulverulent material. All the twyers operate atthe same time, but those that are desired to have less effect operateunder reduced pressure sufficient to prevent the metal from running intothe twyers if the construction of the vessel would cause the metal torun into the' twyers backward, and consequently into the atomizer-boxesif the pressure should stop. Besides getting a homo- The accugeneousmixture of the molten metal and the purifying agents by injectionthrough the side twyers the blowing of the air in all directions intothe bodyof metal, more particularly nearer the surface, willproduceatough and solid metal, as well as being free from undesirableelements. The operation of blowing in the finely-divided material iscommenced at the lower side twyers and gradually works up as thecontents of the carbon decreases,

and toward the end all the side twyers are in use, though a largerquantity is injected by the twyers near the bottom or hearth. When thefinal stage arrives, the air-supply valves are partially closed and thecover or lid on the converter nose or outlet is nearly shut. The

blast is continued gently until the proper vacuum is obtained in areservoir situated between the converter and the vacuum-pump, and whensuch is the case the converter is rechned so as to clear the twyers, thelid or-nosetightly shut, as are also the blast-valves, while the valvesthat control the atomizers are suddenly opened, which draws in thematerial,-

and after a few minutes the converter is emptied into ladles. j i i Theprocess is carried out in special vessels and is subject to variationsto suit conditions. The amount of air blown in and the quantity of thepurifying agents introduced depends upon the grade of steel desired andthe amount of impurities in the metal, and except where otherwise statedthe operation is conducted in the ordinary manner.

Having described my invention, what I claim, and desire to secure byLetters Patent,

-1. The introduction of purifying agents in afinely-divided state intomolten iron and steel by means of the atmospheric air-blast at variablepressures into differentdepths of the metal in a refractory-linedconverter or vessel, as described.

2. The introduction of dephosphorizing material in a pulverulent form,in the manufacture of steel, by means of the air-blast under pressure indifferent thickness or depths of the molten metal and by drawing in thedephosphorizing material at a certain stage of the process by means of avacuum, and the expulsion of the gases from the vessel on theintroduction of, the purifying material into the converter,substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

WALTER B. BURROW.

Witnesses: I

J. M. NEWBERN, JOHN L. FLETCHER.

ITO

